Mention endianness and alignment in section ArrayBuffers, binary arrays

* Alignment: My browser (Firefox 87.0 on Linux x86_64) doesn't let me create an unaligned Uint16Array. I. e., `new Uint16Array(b, 1, 1)` on a 4-byte array buffer gives `RangeError: attempting to construct out-of-bounds TypedArray on ArrayBuffer`. In the standard that is [22.2.1.5](https://262.ecma-international.org/6.0/#sec-%typedarray%-buffer-byteoffset-length).13a.

* Endianness: Uint16Array is little-endian on my machine. I just learned that this is machine dependent ([https://stackoverflow.com/questions/7869752/javascript-typed-arrays-and-endianness](Stackoverflow)). In contrast, `dataView.getUint16()` is big-endian, unless the second argument is true.

Hope this helps.

找到标题为“ArrayBuffers, binary arrays”的教程部分，并检查其中关于类型化数组和 DataView 的现有说明。添加清晰的注释，涵盖 issue 中描述的对齐限制和字节序区别，包括 Uint16Array 和 dataView.getUint16() 的相关行为。当读者能够从该部分理解这两个注意事项时，即可视为完成。

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